Method of producing liquid fuel

Abstract

The present invention provides a method of producing a liquid fuel enabling production of middle distillate at a high yield from a feed oil containing paraffinic hydrocarbons having 20 to 100 carbon atoms as main components without losing the high cracking activity and also enabling provision of high quality gas oil included in the middle distillate. A feed oil containing paraffinic hydrocarbons having 20 to 100 carbon atoms as main components is subjected to hydrotreating in the present of a prespecified hydrotreating catalyst and under the conditions for hydrotreating including a temperature of 200 to 350° C., a liquid hourly space velocity of 0.1 to 5.0 h−1, and a partial pressure of hydrogen of 0.5 to 8 MPa to obtain an effluent oil, and then the effluent oil is fractionated to obtain middle distillate including a gas oil with a cetane number of 75 or over and a pour point of −27.5° C. or below at a yield of 55% or over against a total weight of the feed oil.

1. A method of producing a liquid fuel comprising the steps of:
 hydrotreating an FT wax produced by a Fischer-Tropsch synthesis containing
 paraffinic hydrocarbons each having 20 to 100 carbon atoms as main components in a presence of hydrotreating catalyst at a temperature of 200 to 350° C., 
 at the liquid hourly space velocity of 0.1 to 5.0 h −1 , and 
 under a partial pressure of hydrogen in a range from 0.5 to 8 MPa to obtain an effluent oil; and 
 
 fractionating the effluent oil to obtain middle distillate including a gas oil with a cetane number of 75 or more and with a pour point of −27.5° C. or lower at a yield of the middle distillate oil of 55% or more with respect to a total weight of the FT wax, 
 wherein the hydrotreating catalyst includes an active metal component comprising platinum or palladium supported on a carrier containing an amorphous solid acid, and 
 a ultra-stable Y-type zeolite with
 an average particle diameter of 0.2 to 1.0 μm, 
 a crystallinity of 1.02 to 1.10 based on a standard Y-type zeolite basis, and 
 a specific surface area of 700 to 790 m 2 /g, and also 
 
 the hydrotreating catalyst has functions of dehydrogenating, isomerizing, hydrocracking, and hydrogenating hydrocarbons. 
 
     
     
       2. The method of producing a liquid fuel according to  claim 1 , wherein the ultra-stable Y-type zeolite has a silica-alumina molar ratio of 20 to 50. 
     
     
       3. The method of producing a liquid fuel according to  claim 1 , wherein the ultra-stable Y-type zeolite is contained at a concentration of 0.5 to 6 mass % relative to a total weight of the carrier. 
     
     
       4. The method of producing a liquid fuel according to  claim 1 , wherein the ultra-stable Y-type zeolite is prepared by ion exchanging an Na Y-type zeolite with ammonium ions thereby obtaining an ion-exchanged zeolite and then dealuminating the ion-exchanged zeolite in heated steam. 
     
     
       5. The method of producing a liquid fuel according to  claim 1 , wherein the amorphous solid acid includes one or more selected from the group consisting of amorphous silica alumina, amorphous silica zirconia, and amorphous alumina boria. 
     
     
       6. The method of producing a liquid fuel according to  claim 1 , wherein a ratio of a mass (m) of the ultra-stable Y-type zeolite contained in the carrier versus a mass (n) of the amorphous solid acid (n/m) is in a range from 1 to 60. 
     
     
       7. The method of producing a liquid fuel according to  claim 1 , wherein the active metal component is contained as a metal by 0.02 to 2 mass % relative to a total weight of the carrier. 
     
     
       8. The method of producing a liquid fuel according to  claim 1 , wherein the FT wax contains the paraffinic hydrocarbons by 70 mass % or more. 
     
     
       9. The method of producing a liquid fuel according to  claim 1 , wherein the FT wax contains oxygen-containing compounds by 10 mass % or less and/or olefin by 20 mass % or less. 
     
     
       10. The method of producing a liquid fuel according to  claim 1 , wherein the middle distillate contain oxygen-containing compounds by 0.1 mass % or less.